Method for continuous cooking and sterilization of liquids and suspensions



Jan. 10, 1967 R sMlTH ET AL 3,297,448

METHOD FOR CONTINUOUS COOKING AND STERILIZATION OF LIQUIDS ANDSUSPENSIONS Original Filed May 23, 1958 4 Sheets-Sheet 1 INVENTORS-RICHARD A.JMITH FRANCIS W JNAIZ.

their a 7- T'aaa/s, KS

Jan. 10, R s n- ET AL 3,297,448

METHOD FOR CONTI NUOUS COOKING AND STERILIZATION OF LIQUIDS ANDSUSPENSIONS Original Filed May 23. 1958 4 Sheets-Sheet 2 DEAEJZATOJZ.

SECONDARY vrvalzsroJ VALVE, 78 42 79 PRIMARY DIVERSION VA LVL IN ENTORS.RICHARD -5MIT'H FRANCIS WQJNAB.

their A 7' TOfA/B Y3,

Jan. 10, 1967 R s n- ET AL 3,297,448

METHOD FOR CONTINUOUS COOKING AND STERILIZATION OF LIQUIDS ANDSUSPENSIONS Original Filed May 23, 1958 4 Sheets-Sheet INVENTORS.RICHARD A SMITH FRANCIS WQJ NAB.

MTM M/ Jan. 10, 1967 R. A. SMITH ET AL 3,297,448

METHOD FOR CONTINUOUS COOKING AND STERILIZATION OF LIQUIDS ANDSUSPENSIONS Original Filed May 23, 1958 4 Sheets-Sheet 4 /26&.

INVENTOR-S. RICHARD A. SMITH FJZA NCIS WOJNAR. BY

their .wm AKEYS.

United States Patent 3,297,448 METHOD FOR CONTINUOUS COOKING ANDSTERILIZATION 0F LIQUIDS AND SUSPEN- SIONS Richard A. Smith, Gibsonia,and Francis Wojnar, Cheswick, Pa., assignors to H. J. Heinz Company,Pittsburgh, Pa., a corporation of Pennsylvania Original application May23, 1958, Ser. No. 737,430, new Patent No. 3,139,812, dated July 6,1964. Divided and this application June 26, 1964, Ser. No. 388,744 4Claims. (Cl. 992.11)

This application is a division of our application Serial No. 737,430,filed May 23, 1958, now Patent No. 3,139,812, granted July 6, 1964.

This invention relates to the so-called flash cooking and sterilizationof liquids and suspensions of solids in liquids, and especially foodproducts which, after being cooked and sterilized, are placed in cansand sealed, and is for a continuous process of flash cooking andsterilization.

The invention has for its primary object to provide a continuous methodand apparatus for raising the temperature of the product to sterilizingtemperature instantaneously and thereafter holding it at suchtemperature for the required period of time and cooling it after therequired time and discharging it into a vessel from which it may beplaced in cans.

A further object of the invention is to provide a cooking andsterilizing method and apparatus which will be substantially automaticand at the same time yield a product of improved quality.

A further object of the invention is to provide a sterilizing systemwhich is designed to handle large volumes of product and assure uniformprocessing of the product before it is delivered to the cans.

These and other objects and advantages are secured by this invention aswill be apparent to those skilled in the art.

While the invention is applicable to the processing of varioussubstances, it has been especially developed for the processing of soupand liquids in which either finely divided or chunky solid ingredientsmay be carried or suspended.

By way of explanation, it may be pointed out that food products of thistype are generally processed in kettles in batches, and heat istransferred to the contents of the kettle through the walls of thekettle. To secure adequate heating in a reasonable period of time, thewalls of the kettle are usually heated to a temperature higher than thetemperature required in the product itself. This results in overheatingthe product adjacent the sides and bottom of the kettle, introduces apossibility of scorching, and various ingredients such as oils, fats,and food solids are not simultaneously and uniformly subjected to thesame temperature for the same period of time. This is detrimental to theproduct as is also the inclusion of air during cooking, which impairscolor, flavor and even nutritional values of the food being processed.

In the present invention the product is almost instantaneously anduniformly brought to the desired temperature and not exposed to heat inexcess of the desired maximum, while the product is deaeratedsimultaneously with its exposure to heat, resulting in preserving moreof the natural flavor, color and nutritional values.

The invention may he more fully understood by reference to theaccompanying drawings, in which:

FIG. 1A is a schematic view, largely in the nature of a flow sheetshowing one part of the system;

FIG. 1B is a similar view showing the remainder of the system;

FIG. 2 is a detail of a steam inlet nozzle used in the flash sterilizer;

Patented Jan. 10, 1967 FIG. 3 is a horizontal section in the plane orline III III of FIG. 1A;

FIG. 4 is a diagram of the instrumentation of the system;

FIG. 5 is a vertical section through a product suspension apparatuswhich has proved especially useful for products having fine solids insuspension; and

FIG. 6 is a view similar to FIG. 5 for a similar apparatus to be usedwith products having chunky solids in a liquid vehicle.

The invention will be first described in connection with the processingof liquids, such as broth or soup, as tomato soup, in which any solidsare of minute size.

Referring first to FIGS. 1A and 1B, these two views are complementaryparts of a single drawing, but for clarity of illustration and to avoidreducing the drawing to such size that the necessary detail would belacking, two separate sheets have been used. In these drawings 2designates a storage tank with a cover 3. Within the tank is an agitatoror mixer 4 driven by a motor 5 to prevent sedimentation and mix incomingproduct with that already in the vessel. The product is delivered to thetank 2 through a pipe 6 supplied from one or more mix tanks, the levelof the incoming product being controlled by a float valve 7.

At the bottom of the tank 2 is a discharge pipe 8 leading to the intakeof a pump 9 which discharges into pipe 10 having a line strainer 11therein, which strainer would not be used where a product containingsolids of a coarse nature is used. The pump is driven by a variablespeed drive 12, such as a Reeves Vari-Speed motor with a controlservoamotor 13, as described in our Patent 3,139,812. This is apneumatic diaphragm type servomotor, well known in the art, and which iscoupled to the variable speed drive to maintain the required pump speed.

The pipe 10 leads to a spray nozzle 14 in the upper end of a closedenvironment such as vapor tank 15 of generally cylindrical form. Insidethe vapor tank there is a cylindrical liner wall 16 spaced from thewalls of the vessel 15 and extending throughout the greater portion ofthe height of the vessel 15. This liner is a bafile which prevents anyliquid from spraying against the walls of the vessel 15, as these wallsmight be somewhat cooler than the prevailing temperature in the vessel.

Inside the vessel 15 at a level well below the nozzle 14 is anupwardly-directed steam discharge nozzle 17 which is at the end of thesupply pipe 18. A suitable nozzle comprises a radially slitted disk asshown in FIG. 2. Steam in regulated volume and pressure is supplied topipe 18 to maintain the desired pressure and temperature conditions inthe vapor tank, and the nozzle 17 has adequate openings to preventexcessive back pressure in the pipe 18 within the vapor tank, as a hightemperature of this pipe would cause soup contacting the exterior toburn, but below the temperature where vaporization of the liq id takesplace at the pressure in the vapor tank. The control valve for supplyingthe steam is indicated schematically at'19 and there may be a pressurereducing valve (not shown) ahead of this. With this nozzle superheatedor saturated, steam at the required pressure to provide a sterilizingtemperature may be maintained in the environment 15. I

The bottom 20 of the tank is concaved to form a preferably shallow orsmall capacity catch basin. The interior of the bottom has severalvertical bafile plates 21 to prevent swirling of the liquid as it flowsout discharge pipe 22 at the center of the bottom. A minimum practicallevel of product is maintained in the concave bottom, and forcontrolling the liquid level there is a pilot valve float level control(such as a Fisher Pilot Valve Float Level Control), this being astandard piece of equipment schematically illustrated at 23, this devicehaving a fioat controlled valve that governs the flow of air from apressure supply line 24 to line 25 leading to the control 13 for thevari-speed drive 12 that drives pump 9. If the level in 20 tends to riseabove the minimum, the pump 9 is slowed down, reducing the flow ofliquid to the vapor tank, and if the level tends to reduce below theminimum, the speed of the pump is increased. The level is thereforemaintained by changing the rate of flow of liquid to the vapor tank, thespecific pieces of mechanism here used being standard well-known units.

In this part of the apparatus the entering liquid to be processed issprayed into the vapor tank 15 and as the spray falls through theatmosphere of steam at the desired temperature and pressure, theindividual drops resulting from the spray are exposed to the surroundingatmosphere of steam and are thereby almost instantaneously raised tosterilizing and cooking temperature under superatmospheric pressure.This rapid heating under pressure preserves the flavor a-nd color of theproduct and also releases entrained air, or deaerates the soup, theremoval of air being important in the preservation of color and flavor.

For removing air there are two vent pipes 26 and 27 leading from a levelclose to the top of the liquid level, and a third pipe 28 leads fromnear the top of the vapor tank. Each of these lines is throttled throughvalves 26', 27 and 28' respectively to permit a continuous bleed ofsteam from the vapor tank, and of course air will be carried away withthe escaping steam. The three pipes 26, 27 and 28 terminate at the topof the storage tank so that condensate and condensible vapors havingaromatic qualities are returned to the feed mix. A safety valve 27a isindicated in line 27 to relieve the vapor tank should pressure for anyreason rise above a desired level. The steam which escapes through thevents above referred to is throttled to a degree where pressure ismaintained in the vapor chamber without diificulty.

The pipe 22 is surrounded with insulation so that the product flowingthrough the pipe is held at sterilizing or cooking temperature. At 29there is a second pump similar to pump 9 driven by a variable speeddrive 30 similar to drive 12 with a diaphragm type control 31 similar tocontrol 13. From the discharge pump, the liquid then flows throughanother insulated holding section of pipe 32.

At the end of the holding section 32 there is a primary diversion valve33 which is air-actuated, this diversion valve being a three-way valve.Under normal operating conditions the liquid flows from pipe 32, throughvalve 33 into pipe 34 at the intake end of a heat exchanger or cooler35. In the other position of the three-way valve, the liquid is divertedfrom the cooler into a pipe 36.

The diversion valve may be what is known commercially as a three-waysanitary valve.

The cooler 35 is of any conventional form, with a pipe 37 through whichthe soup flows and a surrounding chamer 38 through which water from asupply pipe 39 circulates, the water being discharged from the coolerthrough a pipe 40.

The soup or other liquid product leaves the cooler through pipe 41,flowing through pressure relief or back pressure valve 42 the-rein, andfrom the back pressure valve through pipe 43 to the inlet side of asecondary diversion valve 44, this being similar to the primarydiversion valve. Under normal operating conditions this diversion valvepasses the product into a pipe 45 which enters the top of a deaeratorvessel 46, the pipe 45 having a perforated discharge terminal 47thereon.

The deaerator 46 has a vapor vent 48 at the top leading to atmosphere,and at the bottom is a discharge pipe leading to the filling machines orother point of disposal. The interior of the deaerator is atatmospheric, or could with some products, be at sub-atmosphericpressure, which could be accomplished by connecting a suction fan tovent pipe 48. The distance from the back pressure valve to the deaeratoris kept as short as possible, for the reasons hereinafter explained.

The other outlet of the secondary diversion valve 44 leads to pipe 46athat returns the rejected product to the tank 2.

The purpose of the diversion valves is to assure that any product thatreaches the deaerator will have been held at the sterilizing temperaturefor the required period of time. For this purpose there is temperatureresponsive control or temperature bulb in the discharge pipe 22 close tothe vapor tank. If the temperature of the product leaving the vapor tankis too low, this bulb will operate the primary diversion valve 33 todivert the flow of product into line 36.

By way of explanation it may be pointed out first that the primary andsecondary diversion valves are so connected and controlled that thesecondary diversion valve is always open when the primary diversionvalve is open, but the secondary diversion valve may open without theprimary diversion valve being opened. In this way any product that isnot heated sufficiently or which is overcooled is rejected and returnedthrough pipe 49 to the tank 2.

The operation of the primary diversion valve may best be explained byreference to FIG. 4. The diversion valve 33 is a well-known type ofdiaphragm valve which is biased to divert the flow from the normal pathif there is no air pressure on the diaphragm. As long as there is airpressure on the diaphragm, the liquid being processed will fiow in thenormal path through the cooler. There is a temperature-responsive bulb50 above referred to in the line 22 close to the outlet of the vaportank. This bulb is connected through a capillary tube 51 to a controller52. The control instrument 52 is an apparatus available commerciallysuch, for example, as that indicated in our Patent No. 3,139,812. Itincludes both recording and control functions. Under normal operatingconditions air pressure fiows from an air supply pipe 520 'into branchpipe 53, into a pilot valve 54 having an inlet port B and an outlet portC. This is a pilot valve of well-known commercial type having aninternal valve element which is so ported as to normally establish aflow from the intake port at B to an outlet port at C. The air from Cflows through pipe 55 to the disphragm chamber 33a of the primarydiversion valve 33. Pipe 53 also connects to the instrument 52, andthrough instrument 52 into pipe 56. From pipe 56 air can flowthrough acheck valve 57 into a system that includes one or more air reservoirs58. There is a pipe 59 that also leads from the reservoirs and the checkvalve to the bottom of the pilot valve 54. In addition to this there isa pipe 60 having a needle valve 61 therein. The internal construction ofthe controller 52 is such that if the temperature affecting the bulb 50drops a predetermined amount, say 2, a connection will be establishedfrom pipe 53 to pipe 56 so that high pressure air will flow from pipe 53into pipe 56, thence through the check valve 57 and pipe 50 to thebottom of the pilot valve 54, and at the same time cause air to flowinto the reservoirs 58. When air flows through the pipe 59 to the bottomof the pilot valve, the slide element in this valve will be moved toconnect port C with a port at A, which vents the line 55 to atmosphere,thereby relieving the pressure in the diaphragm chamber 33a of thediversion valve, causing this valve to move to diverting position.

As soon as the soup or other liquid coming from the vapor tank reachesthe proper temperature, the bulb 50 Will respond to operate the controldevice 52 to open pipe 56 to atmosphere and break the connection betweenpipes 53 and 56. However the flow of liquid must continue to be diverteduntil all the liquid in the line between the bulb 50 and the primarydiversion valve has been diverted, and liquid of the proper temperaturehas reached the primary diversion valve. This delay in the operation ofthe primary diversion valve to normal position for purging the systemafter the temperature bulb responds to normal temperature condition issecured by adjusting the needle valve 61 so that air that hasaccumulated in the reservoirs 58 will bleed otf very slowly, maintaininga pressure in line 59 and the bottom of the pilot valve 54 for theperiod of time required under normal conditions for the liquid of propertemperature to reach the diversion valve. In this way it is assured thatwhen starting up, or at the time that the temperature falls below thedesired sterilizing temperature, none of the product which is too cold,or which has been insutficiently heated, will flow into the cooler. Theneedle valve 61 and the capacity of tanks 58 is adjustable for thepurpose of adjusting this time interval to the capacity of the system.

The secondary diversion valve is also of the diaphragmoperated typewhich permits a normal flow of liquid only when pressure is on thediaphragm, and which diverts when the pressure on the diaphragm falls.In FIG. 4 the secondary diversion valve 44 has a diaphragm chamber 45,and there is an air line 62 leading from a port at C of a pilot valve63, this pilot valve being similar to the pilot valve 54. Air from thepipe 52a flows through pipe 64 into the secondary diversion valvecontrol 65, and from this control there is a pipe 66 that leads into thebottom of the pilot valve 63. Pipe 67 leads from pipe on the outlet sideof the pilot valve 54 to inlet port at B of the pilot valve 63. Theinstrument 65 is a No. 122RV563 Taylor Full Scope Temperature RecordingController. In the pipe 41 at the discharge end of the cooler there is atemperature-responsive bulb 68 that is connected through a capillarytube 69 to the controller 65. So long as there is a normal operatingcondition in the first diversion valve and bulb 68 is responding tofluid of the proper temperature at the discharge outlet of the cooler,air will flow from the pipe 55 on the outlet of the pilot valve 54,through pipe 67 to the inlet port at B of the pilot valve 63, andthrough this inlet port B to the outlet port at C, and thence throughpipe 62 to the secondary diversion valve diaphragm chamber 47a. Howeverif the pressure fails in line 67, pilot 63 will vent to the atmospherethrough a port at A, and the secondary diversion valve will also move tothe diverting position. The instrument 65, upon a decrease intemperature afl'ecting the bulb 68, is designed to connect the line 64with the line 66 causing the pilot valve to move to a position where theline 62 is vented to atmosphere and communication between ports B and Cis cut off.

It will thus be seen that the secondary diversion valve will never closeunless there is pressure in the line 67 to close it, and that it willopen if this pressure fails, or if the instrument 65 signals it to open.Thus the secondary diversion valve will be open at any time that theprimary diversion valve is open and will close only if the primarydiversion valve is closed, but the secondary diversion valve may alsoopen and close independently of the primary one.

In the outlet line 40 for the cooling water there are hand valves 68 and69 and a by-pass 70 with a hand valve 71 therein. Between the valves 68and 68a there is also a pressure-operated throttle valve 72, which canbe set to regulate the flow of cooling water. This is normally held inopen position by air from the pipe 64 passing through the seconddiversion control 65 and pipe 73 leading from the second diversioncontrol to the valve 72. This control regulates the flow of coolingwater so that the temperature drop of the product flowing from thecooler may be maintained at a predetermined level. For the processing oftomato soup the product coming from the cooler should be at 220 P. sothat the second diversion control regulates the flow of cooling water tomaintain this temperature. If the product is over-cooled the sensingbulb 68 will operate the secondary diversion control, and at the sametime open line 73 to the atmosphere, causing the valve 72 to close. Anyproduct that is below 220 P. will then be diverted through line 49 backto the storage tank 2.

The control valve system is placed in the outlet line 40 so that if theflow of water is shut off the cooler will remain full of water andthereby prevent the product from burning on to the interior of thecooling coil 37. As soon as the sensing bulb 68 indicates that the temperature of the product is up to 220 F. or the desired dischargetemperature, it will operate the second diversion control to restore thesecondary diversion valve to its normal position, and at the same timeopen the valve 72 to restore the normal flow of cooling water.

The product-which flows through pipe 45 into the deaerator thus entersthe deaerator at 220 F. and is sprayed into the deaerator chamber wherethe release of pressure immediately causes it to flash down to 212 F.The steam which is liberated will be vented to the atmosphere, therebyridding the product ofsome of the steam Which is condensed into theproduct in the vapor chamber. Also when the product is flashed from 220F. to 212 F., any remaining air entrained in the product will bereleased and vented through the pipe 48. The deaerator 46 has suflicientcapacity so as to act as a reservoir whereby there may be a uniform flowto the filling machine notwithstanding slight variations that may occurin the sterilizing operation. A float 74 may be provided in thedeaerator 46 for stopping the pump 29 if the level in the deaeratorrises above a predetermined limit, this being effected electricallythrough a contact 75 in a well-known manner not important to the presentinvention. The same float 74 may light a signal light (not shown) byoperating a contact 76 when the product falls below a predeterminedlevel in the deaerator.

The back pressure valve 42 is governed by a back pressure controller 77(see FIG. 4). This controller is connected through a capillary tube 78with a pressure-responsive device 79 connected into the pipe 41 inadvance of the valve 42. The pressure-responsive device is a wellknownpiece of apparatus such as a Crosby Pressure Bowl. It responds to anyvariation in pressure in the line 41 and communicates such change to theback pressure controller 77. The back pressure controller 77 controlsthe flow of air from supply line 52a into pipe 80 leading to a diaphragmchamber 81 for actuating the back pressure valve. The back' pressurecontroller is set to maintain a predetermined pressure in the line 41,and if the pressure drops, controller 77 actuates the diaphragm 81 torestrict the discharge of the product into the line 43, and if thepressure rises above a predetermined point, the reverse operation takesplace to further open the back pressure valve. The back pressure valveis used to prevent the product from flashing back into the cooler,assuring sufficient pressure being maintained on the product to keep itat the 220 F. temperature. It is because of this that all piping betweenthe back pressure control valve 42 and the deaerator is kept as short aspossible, as there will be a tendency for a flash-back in this line tothe back pressure control valve.

Close to the outlet of the pump 29 in the holding section 32 is aflowrator 82. This responds to the rate of flow of the product throughthe holding section, and it is connected through electric leads 83 and84 with a control 85. This control is also a well-known type ofequipment, being part of a Fisher-Porter Flowrator. The flowrator 82operates the control unit 85 through which air pressure from pipe 42ainto pipe 87 is regulated. This pipe leads to the diaphragm type control31 for the vari-speed drive 30 that operates pump 29. The control 85 isset to drive the pump at a predetermined rate so that a fixed volume offluid is flowing through the holding section in a given unit of time,say for example, six gallons per minute. Due to wear in the ump, or dueto some change in the heat of liquid being supplied to the pump, or forsome other reason, the pump may deliver less or more than the desiredvolume. In this case the flowrator 82 will act to control the flow ofair from pipe 86 to pipe 87 and thereby operate the vari-speedcontroller 30 to increase or decrease the output of the pump to keep therate of flow constant.

Thus the flowrator operates to maintain the flow of liquid through thesystem at a predetermined rate. This is important since any change inthe rate of flow might result in a change of temperature, or holdingtime of the products at the desired temperature.

In the overall operation of the system the product to be cooked andsterilized is discharged into the storage tank 2 from whence it ispumped to the vapor tank 15 where it is contacted by superheated orsaturated steam and the droplets of spray instantly raised tosterilizing temperature. It is important that the product be sprayedfrom a nozzle so that it is broken up into small drops which areinstantly and uniformly heated to the sterilizing temperature. Animportant feature of the vapor tank is the provision of the baflle 16 sothat there is a curtain of steam between the baflie 16 and the exteriorwall of the chamber, thereby avoiding any cooling or condensation of theproduct on the baflie. The heated product is collected in the bottom ofthe vaporizing chamber and the rate of feed of liquid is controlled bythe float level control 23 operating on the Reeves Vari-speed drive 12to regulate the flow of product to the vapor tank. The liquid flows fromthe vapor tank through pipe 22 and is pumped in the pump 29 through theflowrator 82 and the holding section 32. In starting up the system thefluid will be at a temperature lower than the required temperature andthe holding section 32 will not be up to temperature. Thetemperature-responsive bulb 50 will therefore cause the primarydiversion valve 33 to open and the product will flow through the holdingsection 32 and through pipe 36 to the second diversion valve 44. Thisvalve is open at any time that the primary diversion valve is open, sothat the product will flow through ipe 49 without passing'through thecooler, and be returned to the storage tank 2. When the product is atthe required temperature, temperature bulb 50 willrespond to close theprimary diversion valve, but because of the time lag arrangementprovided by the air chambers 58 and associated mechanisms, this primarydiversion valve will not establish a normal flow until product of therequired temperature has reached the primary diversion valve. If theproduct is then passed through the cooler and is still under the desiredtemperature, the bulb 68 will keep the secondary diversion valve 44 openuntil the product contacting the bulb 68 is at the required temperaturewhen the diversion valve 44 will establish a normal flow to thedeaerator 46. The product will be delivered to the deaerator at apredetermined temperature above 212 F. As stated above, in the case oftomato soup, the product will be cooled in the cooler to 220 F. and willbe flashed in the deaerator to 212 F., and from this the product will bedelivered to the can-filling machines. The system Will then continuouslyoperate in this manner, and if the rate of flow tends to change, theflowrator will correct the rate of fiow by operating the vari-speedcontrol 31 in the manner above described. If the product at any timefails to be at the required temperature, the bulb 50 will respond byoperating the primary diversion valve, and through it the secondarydiversion valve to by-pass any product that is insufliciently heated,until such time as the product has again reached the desired temperatureand the system has purged itself of any insuificiently-heated product.

At the deaerator any entrained air not removed in the injection tankwill be released when the liquid is flashed and removed while asuflicient volume of liquid is mainatined in the deaerator so as tosupply the can-filling machine or machines at a constant ratenotwithstanding interruption in the supply of liquid going through thesterilizing system.

Because of the liquid being sprayed into the vaporizing chamber in veryfine drops, each drop is quickly and practically instantaneously raisedto sterilizing temperature. There is a small volume of liquid in thecatch basin at the bottom of the vaporizing chamber so that the averageretention time of any particle in the chamber is very short. In theholding section of pipe the soup or other liquid does not contact theair. The flash heating serves to maintain the flavor which is not lostin the holding section or in the cooling section.

The modification shown in FIG. shows another form of product injectiontank particularly designed for use where the product has fine solids insuspension, the remainder of the system being the same as previouslydescribed. In this view 15a designates a cylindrical tube forming achamber 15b. At the bottom there is a conical collecting chamber 20awhich delivers product into a pipe 22a corresponding to the productdischarge pipe 22 in FIG. 1A. At the top of the cylindrical body 15athere is a cap 15c removably retained in place by a nut 15d. The productis carried into the chamber 15b through pipe at the center of the cap,this pipe projecting part way into the chamber, and it has a conicaldiverter 14a suspended below it in spaced relation to its end, thediverter being supported by brackets 14b secured to the cone and securedto the lower end of the pipe 10a.

The cap c also has an air bleed pipe 280 carried thereby and passingthrough it, this air bleed pipe corresponding to the pipe 28 of FIG. 1A,and it has a valve 285 for lirnting the flow of air and steam therefrom,this valve corresponding in purpose to the valve 28' of FIG. 1A. Thereis also an air bleed pipe 26a passing through the side of the tube 15a,and it has a valve 26b. This corresponds to the pipe 26 of FIG. 1A andthe valve 26 of that figure. It is slightly above the normal liquidlevel in the unit when it is operating, this level being indicated bythe line X-X.

Near the top of the chamber 15!; there is a high pressure steam supplypipe 181:. Inside the chamber concentric about the pipe 16a there is anannular baffle 94 supported on brackets 95, the baffle having an annularflange 96 that is turned outwardly toward the cylindrical wall 15a, butwhich. terminates in spaced relation to this wall. This baflie serves todivert the incoming stream, and cause it to flow annularly in the space97 between the baflie 94 and the wall of the chamber. The steamcirculates downwardly into the chamber around the edge of the flange 96.

In operation the product entering through the pipe 10a is dischargedagainst the conical diverter 14a and spread into a thin stream by thecone. An atmosphere of steam at the proper temperature is maintained inthe chamber 15b, and the finely divided particles in the liquids areexposed to this atmosphere of steam as they fall through the chamber.They are thus almost instantly raised to the proper sterilizing orcooking temperature, while at the same time being deaerated in themanner described in connection with FIG. 1. In this case the collectingbottom of the suspension chamber is provided by the deep conicalconnector a so as to avoid sedimenta tion of the small particles whichmight occur with a shallow bottom as shown in FIG. 1A.

In the arrangement shown in FIG. 6 the injection tank is designed forthe more efifective processing of products having chunky solids carriedin a liquid vehicle, and here again only the tank is shown since thebalance of the system is the same as shown in FIGS. 1A and 1B and theother figures. In this figure there is an outer tank 100 with a cover101 and a conical bottom 102, the bottom having a discharge pipe 103corresponding again to the pipe 22 in FIG. 1A. There is an air vent 104through the side of the tank corresponding to the pipe 26 of FIG. 1A,and it would of course be controlled by a valve similar to the valve 26,but not shown in this figure. Suspended from the cover 101 inside thetank is a cylindrical inner wall 105 which is spaced from the wall 101).

team is introduced into the tank through pipe 106 which has a T 1107 atits inner terminal for directing the steam into the annular space 108between the side walls of the tank and the inner wall 105.

The product is introduced into the injection tank through the center ofthe cover of the pipe 109 in the cover of the tank and stream isintroduced through one or more tangential steam inlet nozzles 110, thesenozzles entering the lower end of the pipe 1E9 tangentially so as toimpart a disintegrating and whirling action to the product as it isdischarged into the chamber. Below the end of the pipe 109 there is aconical diverter 111 into which the product is discharged, and overwhich it is spread into a relatively thin layer, this layer constantlygravitating toward ahe outer edge of the cone 111. At the outer edge ofthe cone it falls into a reversely sloped or inverted conical baffle112. It flows down this hafiie toward the open center thereof, thiscenter being in turn positioned above a second conical bafile 113similar to the baffle 111. This in turn discharges into a secondinverted conical bathe 114 and again the product is discharged onto athird conical diverter or bafiie 115. The number of such bafiles and thespacing can be arranged to secure the best results for a particularproduct. The edges of the bafiie 115 are spaced from the inner wall 105and the product discharged from it falls into the bottom 102 of thetank. The normal liquid level in the bottom of the tank is indicated bythe line Y-Y. In the cover 101 there is also an air vent pipe 116corresponding to the air vent pipe 28 of FIG. 1A, and which may bearranged similarly to the pipe 28 with a metering or control valvesimilar to the valve 28.

In this tank the baffles act to check the free fall of the solidparticles, so that they are exposed for a longer period of time to theatmosphere of steam inside the vessel before they eventually fall intothe bottom of the tank. By reason of this there is adequate time for thechunky solid particles to be heated throughout to the requiredtemperature, and this temperature is held in the product while theproduct is flowing through a holding section of tubing, as described inconnection with FIGS. 1A and 1B. This arrangement, like the arrangementin FIG. 5, has the further advantage that while the steam is injectedinto the chamber, the discharge pipe for the steam is outside the pathof travel of the product, so that the product cannot collect on the pipeas it may in the arrangement shown in FIG. 1A. The inner wall 105protects the product from contact with the outer wall, and if desired,there may be such a wall in the construction shown in FIG. 5.

In each of the product injection tanks, the product is sprayed or brokenup and is exposed to the atmosphere of steam in a dispersed condition.As a consequence all components and ingredients receive a sudden impactof heat which almost instantaneously effects the temperature increaserequired for cooking and sterilizing and then is held at the requiredtemperature for the necessary time interval. The cooling from asuperheated temperature to 212 F. or lower also occurs with about thesame rapidity. Overheating of some product to insure adequate heating ofthe balance, as with kettles is avoided so that color, flavor, andvitamin and nutrient properties are better preserved, particularly sincemost of the air is removed in the injection tank. To those skilled inthe art it will be appreciated that the uniformity of thermal shock,both on heating and on cooling, assures uniform processing of all oils,fats, and other qualities.

Thus, we have provided a continuous automatic heat processing methodwhich results in both an improved product and which reduces the cost.

The process yields an improved product, and one in which uniform qualitycan he maintained much better than with existing batch methods ofcooking and sterilization. There is a minimum possibility of scorchingor burning any of the product and the rate of processing can berequlated to the capacity of the filling equipment. The product goesinto the cans completely sterilized so that subsequent processing inautoclaves is not necessary.

iii The invention results not only in an improved product, but also in aconsiderable operating economy.

The drawings are of a schematic character since the control equipmentherein described is all standard, well- 5 known equipment constitutingno part per se of our invention, and its exact construction andoperation is wellknown to those skilled in the art. While we haveindicated certain specific pieces of apparatus, this is merely by Way ofillustration and various changes and modifications may be made thereinwithin the contemplation of our invention and under the scope of thefollowing claims.

We claim:

1. The method of heat processing a flowable liquid product comprisingcontinuously transferring liquid from a storage vessel and dispersing itthrough a spray nozzle into the upper part of an enclosed environmenthaving a bottom into which the liquid product gravitates and iscollected,

maintaining an atmosphere of steam in said environment at a constantpressure and temperature with the temperature higher than thetemperature of the incoming product and rapidly heating the liquidproduct to a predetermined temperature,

flowing the liqiud product form said bottom into a tubular holdingsection through which it flows and in which it remains at apredetermined temperature, regulating the rate of flow of the productthrough the holding section to retain the product in the holding sectionfor a predetermined time period,

and regulating the rate of transfer of liquid from the storage vessel tothe spray nozzle by the liquid level in said bottom and thereby limitthe average retention time of the liquid product in the bottom of saidclosed environment.

2. The method defined in claim 1 wherein air and steam are continuouslyvented from the said closed environment but in a restricted flow such asto maintain a predetermined pressure in the closed environment.

3. The method of heat processing a flowable liquid product as defined inclaim 1 wherein the product from the holding section is delivered to acooling unit and wherein the temperature of the product from the holdingsection is continuously monitored and the product which is below apredetermined temperature is diverted back to the storage vessel insteadof flowing into said indirect cooling unit.

4. The method of heat processing a flowable liquid product as defined inclaim 1 wherein the hot liquid 50 product from the holding section isdelivered to a watercooled cooling unit and wherein the temperature ofthe product from the holding section is continuously monitored and theproduct which is below a predetermined temperature is diverted back tothe storage vessel in- 55 stead of flowing into said water-cooledcooling unit, flash cooling the product as it is discharged from thewater-cooled unit to further reduce its temperature and to remove somemoisture which has been condensed 60 into the product in said closedenvironment.

References Cited by the Examiner UNITED STATES PATENTS 2,401,077 5/ 1946Johnston 9921l 2,549,575 4/1951 Conley 99-182 X 2,766,126 10/1956 Hawk99182 2,899,320 8/1959 Davies 99212 X 2,908 577 10/1959 Hawk et al99-182 X 2,999,024 9/ 1961 Stimpson et al 99182 A. LOU-IS MONACELL,Primary Examiner. HYMAN LORD, Assistant Examiner.

1. THE METHOD OF HEAT PROCESSING A FLOWABLE LIQUID PRODUCT COMPRISINGCONTINUOUSLY TRANSFERRING LIQUID FROM A STORAGE VESSEL AND DISPERSING ITTHROUGH A SPRAY NOZZLE INTO THE UPPER PART OF AN ENCLOSED ENVIRONMENTHAVING A BOTTOM INTO WHICH THE LIQUID PRODUCT GRAVITATES AND ISCOLLECTED, MAINTAINING AN ATMOSPHERE OF STEAM IN SIAD ENVIRONMENT AT ACONSTANT PRESSURE AND TEMPERATURE WITH THE TEMPERATURE HIGHER THAN THETEMPERATURE OF THE INCOMING PRODUCT AND RAPIDLY HEATING THE LIQUIDPRODUCT TO A PREDETERMINED TEMPERATURE, FLOWING THE LIQUID PRODUCT FORMSAID BOTTOM INTO A TUBULAR HOLDING SECTION THROUGH WHICH IT FLOWS AND INWHICH IT REMAINS AT A PREDETERMINED TEMPERATURE, REGULATING THE RATE OFFLOW OF THE PRODUCT THROUGH THE HOLDING SECTION TO RETAIN THE PRODUCT INTHE HOLDING SECTION FOR A PREDETERMINED TIME PERIOD, AND REGULATING THERATE OF TRANSFER OF LIQUID FROM THE STORAGE VESSEL TO THE SPRAY NOZZLEBY THE LIQUID LEVEL IN SAID BOTTOM AND THEREBY LIMIT THE AVERAGERETENTION TIME OF THE LIQUID PRODUCT IN THE BOTTOM OF SAID CLOSEDENVIRONMENT.